[PATCH v13 1/8] save/load cpu runstate

Hu Tao
2013-02-28T12:13:23Z

This patch enables preservation of cpu runstate during save/load vm.
So when a vm is restored from snapshot, the cpu runstate is restored,
too.

See following example:

# save two vms: one is running, the other is paused
(qemu) info status
VM status: running
(qemu) savevm running
(qemu) stop
(qemu) info status
VM status: paused
(qemu) savevm paused

# restore the one running
(qemu) info status
VM status: paused
(qemu) loadvm running
(qemu) info status
VM status: running

# restore the one paused
(qemu) loadvm paused
(qemu) info status
VM status: paused
(qemu) cont
(qemu)info status
VM status: running

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
include/sysemu/sysemu.h | 2 ++
migration.c | 6 +-----
monitor.c | 5 ++---
savevm.c | 1 +
vl.c | 34 ++++++++++++++++++++++++++++++++++
5 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index b19ec95..f121213 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -19,6 +19,8 @@ extern uint8_t qemu_uuid[];
int qemu_uuid_parse(const char *str, uint8_t *uuid);
#define UUID_FMT "%02hhx%02hhx%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"

+void save_run_state(void);
+void load_run_state(void);
bool runstate_check(RunState state);
void runstate_set(RunState new_state);
int runstate_is_running(void);
diff --git a/migration.c b/migration.c
index 11725ae..c29830e 100644
--- a/migration.c
+++ b/migration.c
@@ -107,11 +107,7 @@ static void process_incoming_migration_co(void *opaque)
/* Make sure all file formats flush their mutable metadata */
bdrv_invalidate_cache_all();

- if (autostart) {
- vm_start();
- } else {
- runstate_set(RUN_STATE_PAUSED);
- }
+ load_run_state();
}

void process_incoming_migration(QEMUFile *f)
diff --git a/monitor.c b/monitor.c
index 32a6e74..bf974b4 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2059,13 +2059,12 @@ void qmp_closefd(const char *fdname, Error **errp)

static void do_loadvm(Monitor *mon, const QDict *qdict)
{
- int saved_vm_running = runstate_is_running();
const char *name = qdict_get_str(qdict, "name");

vm_stop(RUN_STATE_RESTORE_VM);

- if (load_vmstate(name) == 0 && saved_vm_running) {
- vm_start();
+ if (load_vmstate(name) == 0) {
+ load_run_state();
}
}

diff --git a/savevm.c b/savevm.c
index a8a53ef..aa631eb 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2143,6 +2143,7 @@ void do_savevm(Monitor *mon, const QDict *qdict)
}

saved_vm_running = runstate_is_running();
+ save_run_state();
vm_stop(RUN_STATE_SAVE_VM);

memset(sn, 0, sizeof(*sn));
diff --git a/vl.c b/vl.c
index febd2ea..7991f2e 100644
--- a/vl.c
+++ b/vl.c
@@ -523,6 +523,7 @@ static int default_driver_check(QemuOpts *opts, void *opaque)
/* QEMU state */

static RunState current_run_state = RUN_STATE_PRELAUNCH;
+static RunState saved_run_state = RUN_STATE_RUNNING;

typedef struct {
RunState from;
@@ -546,6 +547,7 @@ static const RunStateTransition runstate_transitions_def[] = {
{ RUN_STATE_PAUSED, RUN_STATE_FINISH_MIGRATE },

{ RUN_STATE_POSTMIGRATE, RUN_STATE_RUNNING },
+ { RUN_STATE_POSTMIGRATE, RUN_STATE_PAUSED },
{ RUN_STATE_POSTMIGRATE, RUN_STATE_FINISH_MIGRATE },

{ RUN_STATE_PRELAUNCH, RUN_STATE_RUNNING },
@@ -556,6 +558,7 @@ static const RunStateTransition runstate_transitions_def[] = {
{ RUN_STATE_FINISH_MIGRATE, RUN_STATE_POSTMIGRATE },

{ RUN_STATE_RESTORE_VM, RUN_STATE_RUNNING },
+ { RUN_STATE_RESTORE_VM, RUN_STATE_PAUSED },

{ RUN_STATE_RUNNING, RUN_STATE_DEBUG },
{ RUN_STATE_RUNNING, RUN_STATE_INTERNAL_ERROR },
@@ -585,11 +588,39 @@ static const RunStateTransition runstate_transitions_def[] = {

static bool runstate_valid_transitions[RUN_STATE_MAX][RUN_STATE_MAX];

+void save_run_state(void)
+{
+ saved_run_state = current_run_state;
+}
+
+void load_run_state(void)
+{
+ if (saved_run_state == RUN_STATE_RUNNING) {
+ vm_start();
+ } else if (!runstate_check(saved_run_state)) {
+ runstate_set(saved_run_state);
+ } else {
+ ; /* leave unchanged */
+ }
+}
+
bool runstate_check(RunState state)
{
return current_run_state == state;
}

+static void runstate_save(QEMUFile *f, void *opaque)
+{
+ qemu_put_byte(f, saved_run_state);
+}
+
+static int runstate_load(QEMUFile *f, void *opaque, int version_id)
+{
+ saved_run_state = qemu_get_byte(f);
+
+ return 0;
+}
+
static void runstate_init(void)
{
const RunStateTransition *p;
@@ -599,6 +630,9 @@ static void runstate_init(void)
for (p = &runstate_transitions_def[0]; p->from != RUN_STATE_MAX; p++) {
runstate_valid_transitions[p->from][p->to] = true;
}
+
+ register_savevm(NULL, "runstate", 0, 1,
+ runstate_save, runstate_load, NULL);
}

/* This function will abort() on invalid state transitions */
--
1.8.1.4